Stabilized antenna system having an acceleration displaceable mass

• US 4,596,989 A
• Filed: 10/21/1983
• Issued: 06/24/1986
• Est. Priority Date: 02/14/1983
• Status: Expired due to Fees

• Current Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Original Assignee: Tracor BEI Incorporated
• Inventors: Smith, Dorsey T., Bieser, Albert H.
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US06/544,445
• Time in Patent Office: 977 Days
• Field of Search: 343/709, 343/710, 343/765, 343/766, 343/716, 33/318, 33/321, 248/182
• US Class Current: 343/709
• CPC Class Codes: H01Q 1/18 Means for stabilising antennas on an unstable platform

Abstract

A stabilized antenna system is disclosed. The stabilized antenna platform includes an acceleration displaceable mass which compensates for linear acceleration forces to inhibit tipping of the antenna platform. The stabilized antenna system may include in combination a gimbal mounting and one or more gyros.

Claims

1. A stabilized platform for use in connection with a satellite antenna mounted to a ship, comprising:

a platform mounted on a gimbal joint which is adapted to be supported upon a ship;

the platform being mechanically coupled to an antenna such that stabilization of the platform will tend to stabilize the antenna and tend to maintain the pointing of the antenna generally in a fixed direction during pitch and roll motions of the ship;

an acceleration displaceable mass adapted to compensate for linear acceleration, the acceleration displaceable mass having an initial position in the absence of linear acceleration;

the platform, the acceleration displaceable mass, and the antenna forming a substantially balanced structure when the acceleration displaceable mass is in said initial position, the structure having a center of gravity located below the gimbal joint;

the acceleration displaceable mass being operable to reduce forces due to linear acceleration tending to destabilize the platform, the acceleration displaceable mass being operable to move to a displaced position, which is spaced from said initial position, in response to linear acceleration of the structure formed by the platform, the acceleration displaceable mass and the antenna, the acceleration displaceable mass being operable to generate an opposing torque when the acceleration displaceable mass moves to its displaced position such that the opposing torque tends to offset the destabilizing forces due to linear acceleration;

the acceleration displaceable mass including a pendulum supported by the platform, where the pendulum is operable to reduce destabilization of the platform caused by linear acceleration forces by moving to a displaced position in response to linear acceleration of the structure formed by the platform, the pendulum and the antenna, the pendulum being operable to generate an opposing torque when the pendulum moves to its displaced position such that the opposing torque tends to offset the destabilizing effects of linear acceleration, the pendulum being operable to return to an initial position when the platform is at rest; and

,

the pendulum having a weight "W_a " which is substantially equal to the product of the total weight of the structure supported upon the gimbal joint "W_s " times the offset "h" of the center of gravity of said structure, all divided by the length "o" of said pendulum.

2. The stabilized platform according to claim 1, further comprising:

a gyro, the gyro being mechanically coupled to the platform so that the gyro'"'"'s resistance to displacement tends to stabilize the platform.

3. The stabilized platform according to claim 1, further comprising:

a first gyro, the first gyro being pivotably mounted upon an axis;

a second gyro, the second gyro being pivotably mounted upon an axis which is generally normal to the axis of the first gyro;

the first and second gyros being mechanically coupled to the platform such than the gyros tend to stabilize the platform.

4. The stabilized platform according to claim 3, wherein:

the axis of the first gyro is generally parallel to the plane of the platform; and

,

the axis of the second gyro is generally parallel to the plane of the platform.

5. The stabilized platform according to claim 1, wherein:

the offset "h" of the center of gravity of said structure is approximately 0.375 inch below the gimbal joint when the pendulum is in its initial position.

6. The stabilized platform according to claim 2, wherein:

the offset "h" of the center of gravity of said structure is approximately 0.375 inch below the gimbal joint when the pendulum is in its initial position.

7. The stabilized platform according to claim 3, wherein:

the offset "h" of the center of gravity of said structure is approximately 0.375 inch below the gimbal joint when the pendulum is in its initial position.

8. The stabilized platform according to claim 4, wherein:

the offset "h" of the center of gravity of said structure is approximately 0.375 inch below the gimbal joint when the pendulum is in its initial position.

9. The stabilized platform according to claim 1, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

10. The stabilized platform according to claim 5, wherein:

the length "o" of tbe pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

11. The stabilized platform according to claim 6, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

12. The stabilized platform according to claim 7, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

13. The stabilized platform according to claim 8, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

14. The stabilized platform according to claim 1, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

15. The stabilized platform according to claim 2, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

16. The stabilized platform according to claim 3, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

17. The stabilized platform according to claim 4, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

18. The stabilized platform according to claim 9, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

19. The stabilized platform according to claim 1, wherein:

a gyro mechanically coupled to the platform is provided so that the gyro'"'"'s resistance to displacement tends to stabilize the platform; and

the platform, antenna and gyro define a pendulous pedestal having a penduluous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

20. The stabilized platform according to claim 3, wherein:

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

21. The stabilized platform according to claim 9, wherein:

a gyro mechanically coupled to the platform is provided so that the gyro'"'"'s resistance to displacement tends to stabilize the platform; and

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

22. The stabilized platform according to claim 12, wherein:

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

23. The stabilized platform according to claim 14, wherein:

a gyro mechanically coupled to the platform is provided so that the gyro'"'"'s resistance to displacement tends to stabilize the platform; and

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

24. The stabilized platform according to claim 16, wherein:

the platform, antenna and gyro define a pendulous pestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at leat 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

25. A stabilized platform for use in connection with a satellite antenna mounted to a ship, comprising:

a platform mounted on a gimbal joint which is adapted to be supported upon a ship;

the platform being mechanically coupled to an antenna such that stabilization of the platform will tend to stabilize the antenna and tend to maintain the pointing of the antenna generally in a fixed direction during pitch and roll motions of the ship;

an acceleration displaceable mass adapted to compensate for linear acceleration, the acceleration displaceable mass having an initial position in the absence of linear acceleration;

the platform, the acceleration displaceable mass, and the antenna forming a statically balanced structure when the accleration displaceable mass is in said initial positon, the structure having a center of gravity located below the gimbal joint;

the acceleration displaceable mass being operable to reduce forces due to linear acceleration tending to destabilize the platform, the acceleration displaceable mass being operable to move to a displaced position, which is spaced from said initial position, in response to linear acceleration of the structure formed by the platform, the accleration displaceable mass and the antenna, the acceleration displaceable mass being operable to ganerate an opposing torque when the acceleration displaceable mass moves to its displaced position such that the opposing torque tends to offset the destabilizing forces due to linear acceleration;

the acceleration displaceable mass including a pendulum supported by the platform, where the pendulum is operable to reduce destabilization of the platform caused by linear acceleration forces by moving to a displaced position in response to linear acceleration of the structure formed by the platform, the pendulum and the antenna, the pendulum being operable to generate an opposing torque when the pendulum moves to its displaced position such that the opposing torque tends to offset the destabilizing effects of linear acceleration, the pendulum being operable to return to an initial position when the platform is at rest; and

,

the pendulum having a weight "W_a " which is substantially equal to the product of the total weight of the structure supported upon the gimbal joint "W_s " times the offset "h" of the center of gravity of said structure, all divided by the length "o" of said pendulum.

26. The stabilized platform according to claim 25, further comprising:

a gyro, the gryo being mechanically coupled to the platform so that the gyro'"'"'s resistance to displacement tends to stabilize the platform.

27. The stabilized platform according to claim 25, further comprising:

a first gyro, the first gyro being pivotably mounted upon an axis;

a second gyro, the second gyro being pivotably mounted upon an axis which is generally normal to the axis of the first gyro;

the first and second gyros being mechanically coupled to the platform such that the gyros tend to stabilize the platform.

28. The stabilized platform according to claim 27, wherein:

the axis of the first gyro is generally parallel to the plane of the platform; and

,

the axis of the second gyro is generally paralllel to the plane of the platform.

29. The stabilized platform according to claim 25, wherein:

the offset "h" of the center of gravity of said structure is approximately 0.375 inch below the gimbal joint when the pendulum is in its initial position.

30. The stabilized platform according to claim 26, wherein:

the offset "h" of the center of gravity of said structure is approximately 0.375 inch below the gimbal joint when the pendulum is in its initial position.

31. The stabilized platform according to claim 27, wherein:

the offset "h" of the center of gravity of said structure is approximately 0.375 inch below the gimbal joint when the pendulum is in its initial position.

32. The stabilized platform according to claim 28, wherein:

the offset "h" of the center of gravity of said structure is approximately 0.375 inch below the gimbal joint when the pendulum is in its initial position.

33. The stabilized platform according to claim 25, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

34. The stabilized platform according to claim 29, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

35. The stabilized platform according to claim 30, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

36. The stabilized platform according to claim 31, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

37. The stabilized platform according to claim 32, wherein:

the length "o" of the pendulum is sufficiently short to give the pendulum a resonant frequency that is slightly below 3 Hz so that the pendulum will have a quick response time without being unduly responsive to vibrations.

38. The stabilized platform according to claim 25, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

39. The stabilized platform according to claim 26, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

40. The stabilized platform according to claim 27, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

41. The stabilized platform according to claim 28, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

42. The stabilized platform according to claim 33, wherein:

the offset "h" of the center of gravity of said structure is within the range of 0.1 to 0.8 inch, when said pendulum is in its initial position.

43. The stabilized platform according to claim 25, wherein:

a gyro mechanically coupled to the platform is provided so that the gyro'"'"'s resistance to displacement tends to stabilize the platform; and

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

44. The stabilized platform according to claim 27, wherein:

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

45. The stabilized platform according to claim 33, wherein:

a gyro mechanically coupled to the platform is provided so that the gyro'"'"'s resistance to displacement tends to stabilize the platform; and

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

46. The stabilized platform according to claim 36, wherein:

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

47. The stabilized platform according to claim 38, wherein:

a gyro mechanically coupled to the platform is provided so that the gyro'"'"'s resistance to displacement tends to stabilize the platform; and

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

48. The stabilized platform according to claim 40, wherein:

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.

49. The stabilized platform according to claim 42, wherein:

a gyro mechanically coupled to the platform is provided so that the gyro'"'"'s resistance to displacement tends to stabilize the platform; and

the platform, antenna and gyro define a pendulous pedestal having a pendulous resonate frequency, the pendulous pedestal having a compound pendulum resonate frequency which is at least 10 times lower than the resonant frequency of the pendulum comprising the acceleration displaceable mass.